I followed the link and found this review...I think I'll try it finally!
For safety concerns just use the source tank valve for on/off control...To fill
each 1 lb. bottle more completely simply put those containers in a refrigerator
or even a freezer for a few minutes AND put the 20/40 lb. FULL tank in hot water
and/or in the Sun...The key here is to maximize the pressure in the source tank
and minimize it in the receiving 1 lb. bottle allowing for more propane to
transfer before the pressure equalizes...I've been filling these little bottles
for years using this type coupler and while they may not get 100% filled as when
new they can reach 80-90% with regularity when the above steps are taken...Keep
in mind NO Propane tank is completely filled anyway or at least it shouldn't be
to allow for excessive heat expansion when full..

Even if trying to
refill in a freezing or below environment simply heating the 20/40 lb. bottle up
by leaving it in a heated indoors for a few hours and/or in hot water will help
tremendously to get more transferred...

When you get tanks refilled
commercially the source has pump assisted pressure so this always allows for a
complete fill...

My dad used to do it for a couple of winters, and I considered trying to refill -- but decided not worth the headache. (I hate the smell of the gas, it gives me a headache) Instead I just switched back to white gas lanterns and am more than pleased with the results. Slightly off-topic, I use 3 lanterns when 3 of us go ice fishing and they keep the canvas house warm all the way down to 10 deg f with the bonus of plenty of light. Canoe camping I might take one, and backpacking I use the miniature stove canisters and campfires.

For a propane ice house heater I like the smaller refillable white tanks.

I just don't see much use for those green canisters except for my propane torch - heavy, expensive if used much, and I have to pay an additional $2.00 or drive 45 minutes one-way to dispose of them.

__________________FB4K - Every October we wrench on donated bikes. Every December, a few thousand kids get bikes for Christmas. For many, it is their first bike, ever. Every bike, new and used, was donated, built, cleaned and repaired. Check us out on FaceBook: FB4K.

Disclaimer: 99% of what I know about cycling I learned on BF. That would make, ummm, 1% experience. And a lot of posts.